1. Field of the Invention
This invention relates to devices having means such as an edge of a slotted plate for penetrating the insulation and making electrical contact with the conductor in which common means cause plural penetrating means to simultaneously engage plural conductors. This invention also relates to connectors in which the conductive portions are immediately surrounded by sealing means which exclude air, moisture and foreign matter. This invention also relates to structure, having means for providing a tight seal between the end structure and the conductor element passing therethrough to the exterior.
2. Description of the Prior Art
A number of connectors for establishing a water-proof splice between a plurality of electrical conductors are known in the art. For example, U.S. Pat. No. 3,410,950 discloses an insulated moisture-proof connecting device utilizing slotted plate members to penetrate the insulation of a pair of conductors to form a splice. A moisture-proof sealant is provided. As the individual wires are terminated, the sealant flows around the interface between the wire and the connector.
A number of moisture-proof electrical connectors utilize a two-piece rigid insulating housing. The two-piece housings utilized in these connectors are positioned in telescoping relationship. Slotted plate contact terminals having wire termination means are generally affixed to one of the two parts of the connector. Wires can be located in alignment with the wire terminating means located on the interior of the housing. As the two housing members are squeezed together, the slotted plate wire termination means penetrates the surrounding conductor insulation and establishes electrical contact with the conductive core. Typically, a moisture-proof sealant is encapsulated within the two-piece housing. As the two pieces are pressed together, the moisture-proof sealant flows around the interface between the contact terminating means and the conductors. U.S. Pat. No. 3,718,888 discloses an electrical connector typical of two-piece telescoping, piston connectors. A device embodying the general principles of U.S. Pat. No. 3,012,219, and shown in U.S. Pat. No. 3,656,088, utilizes a moisture-proof sealant.
Connectors of this type can typically be terminated by utilizing a pair of pliers to squeeze the two housing parts together. Cartridge type termination tools can also be used with connectors of this type. One example of a cartridge type termination tool is found in U.S. Pat. No. 3,707,867. This tool is utilized with a version of a connector shown in U.S. Pat. No. 3,656,088 employing the principles of the device shown in U.S. Pat. No. 3,012,219 referred to above. This version of that connector is depicted in U.S. Pat. No. 3,707,867.
Termination of conductors in these two-piece piston connectors results in a reduction in the interior volume of the connector assembly. As a result, the moisture-proof sealant stored in the connector is "pumped" through the conductor receiving passageways and out of the connector. Statistically, this pumping action tends to result in unsealed gaps, exposing the electrical contact interface to moisture. Another type of failure which has been encountered is the creation of capillary-like passages in the sealant as entrapped air is subjected to a pressure differential during termination and forced through the viscous sealant.
Piston-type connectors do not readily lend themselves to complete encapsulation of the sealant. Since there is a marked decrease in the interior volume of a piston-type connector during termination, initially filling the inner chamber results in an excessive overflow during termination. A partially filled inner chamber results in the pumping of air and sealant during termination. This simultaneous pumping can result air passages and unsealed gaps.
An additional problem is the mess created by the overflow of sealant during wire insertion and termination. This excess sealant might also clog up the tool, used to terminate the connector.
Finally, the piston-type connectors can suffer from adverse temperature-cycling effects, which are especially significant in the presence of entrapped air. The coefficient of expansion of air is markedly different from that of the connector components, or the grease. The larger volume changes of the entrapped air due to a given change in temperature leads again to an undesirable pumping action and results in an alteration of the connector-sealant configuration. Such pumping would result in the creation of external air passages allowing the entrance of water.